Most of the conventional lubricants currently used to lubricate the compressor in air conditioning systems, and particularly in automotive air conditioning systems, are naphtha-based and paraffin-based oils. All of these oils have additives to reduce foaming and to improve lubricity.
Due to environmental factors, the use of chlorinated fluorocarbons (CFC) as refrigerants is being curtailed. Some of the refrigerants which are replacing CFC are incompatible with the conventional lubricants. Therefore, new lubricants are being used. Among these new lubricants are the polyakyleneglycol (PAG) lubricants which also have additives. However, not all of the PAG lubricants, and their additives, are compatible with one another and it is highly probable that the manufacturers of air conditioning equipment will utilize different PAG lubricants in their air conditioners. This will cause problems for persons servicing the air conditioners since mixing of the PAG lubricants among themselves and/or with conventional lubricants, can cause system failure. A further complication in the use of the PAG lubricants is the extreme hydroscopicity of these compounds. The PAG lubricants cannot be dispensed from an open container in a conventional manner. The PAG lubricants must be maintained isolated from the air, and any source of moisture of water.
Therefore, apparatus for dispensing the PAG lubricants must have features which are not required for dispensing conventional lubricants.
A collapsible, accordion fold oil container attached directly to the input of a refrigeration system and adapted to be manually compressed is disclosed by U.S. Pat. No. 2,394,081 issued to Lawton. A portable hand pump for oiling is disclosed by U.S. Pat. No. 2,710,710 issued to Brenholt. U.S. Pat. No. 3,016,022 issued to Roth discloses a manually controlled pump having an internal toggle linkage. A valve assembly for an aerosol container is known in U.S. Pat. No. 3,441,177 issued to Treharne, Jr. U.S. Pat. No. 3,795,262 to Post discloses a manual pump used to inject fluid into a high pressure refrigeration system from a collapsible container. The pump includes check valves to prevent pressure from the refrigeration system from forcing refrigerant back into the fluid container. The sides of the flexible diaphragm are squeezed to provide the preferred method of forcing the fluid into the system. A dispensing pump having a reciprocal plunger is disclosed in U.S. Pat. No. 4,033,487 issued to Micallef. U.S. Pat. No. 4,159,067 issued to Akers discloses a dispensing pump for a container wherein the container can be shipped with the pump assembly attached and removal of the assembly from the container is inhibited. U.S. Pat. No. 4,467,620 to Bradley et al disclose a manual metering pump used to inject oil into the high pressure side of a refrigeration system. The pump includes a pump cylinder having a piston therein actuated by a piston rod. The chamber within pump cylinder containing oil communicates with a fitting through conduit, that attaches to a charging port on the high pressure side of a refrigeration system. The piston rod screw threadably engages the end of piston.
While a variety of dispensing apparatuses are known, none are capable of dispensing hydroscopic lubricants in measure quantities and also providing means to prevent non-compatible materials from being introduced into the air conditioning system at normal system pressures.